This invention is concerned with improving the performance and reliability of pop-up water delivery nozzles employed in swimming pool cleaning systems.
A number of pool cleaning systems have been devised utilizing strategically placed pop-up nozzles which are intermittently supplied with pressurized water. In repose, or inactive, each nozzle is retracted into a body so that its top surface is flush with the pool surface. When activated with pressurized water the nozzle rises above the pool surface and directs a stream of water across the surface to dislodge deleterious material from the surface and place it in suspension so it can be removed by the pool filter. Typically, such nozzles are caused to rotate a small amount about their axes with each activation so that a different area of pool surface is swept with each activation.
U.S. Pat. No. 4,322,860, granted Apr. 6, 1982 to Henry D. Gould for xe2x80x9cPool Cleaning Head with Rotary Pop-Up Jet Producing Elementsxe2x80x9d discloses such a pop-up nozzle. The mechanism for retracting and rotating the Gould nozzle employs a spring and cams and cam followers which are susceptible to breakage in use.
The same lack of reliability can be attributed to the nozzles disclosed in U.S. Pat. No. 4,371,994 granted Feb. 8, 1983 to Lester R. Mathews for xe2x80x9cRotational Indexing Nozzle Arrangementxe2x80x9d, and U.S. Pat. No. 5,251,343, granted Oct. 12, 1993 to John M. Goettl for xe2x80x9cSwimming Pool Pop-Up Fittingxe2x80x9d.
Somewhat simpler nozzles are disclosed in U.S. Pat. No. 4,391,005 granted Jul. 5, 1983 to John M. Goettl for xe2x80x9cApparatus for Cleaning Swimming Poolsxe2x80x9d, U.S. Pat. No. 4,792,095 granted Dec. 20, 1988 to Paul J. Pristo et al. for xe2x80x9cBuffered, Fluid Dispensing Nozzle Unitxe2x80x9d, and U.S. Pat. No. 4,939,797 granted Jul. 10, 1990 to John M. Goettl for xe2x80x9cWater Delivery Assembly for Cleaning Swimming Poolsxe2x80x9d. All of the nozzles disclosed in these patents rely on metal weights to retract the nozzle. However, these nozzles are susceptible to jamming from debris and also there is the possibility of fatigue of plastic components.
There continues to be a need for a more reliable delivery system.
Although the water delivery system of this invention has many features which contribute to its performance and reliability, the feature stressed in this application is the ease of changing the water delivery characteristics of the system.
Depending upon the location of a nozzle in the pool it may be called upon to determine more or less water across the pool surface.
In accordance with this invention the water delivery characteristics of any one water delivery system is altered by selecting and installing different nozzle caps which fit over the upper nozzle portion of the movable stem in the delivery system.